How to prevent 2 seperate meshes that have soft-body modifiers from clipping into each other and glitching, even if collision is turned on?
As with all simulations, start by ensuring you have ‘applied scale’ on each mesh and that the Normals are pointing in the correct direction.
Next, check the ‘cloth and soft body’ settings on each collision modifier - turn the Inner and Outer right down. If you still get intersections, turn the Inner up slightly until it is resolved (but not too high).
Also, you should avoid starting the simulation with intersecting meshes since this can cause very large forces at the start of the simulation.